1. Field of the Invention
The present invention relates to a device for fastening an article to a wall board. More particularly the invention relates to such a device that has a bolt component that mounts an anchor portion with a configuration that is resiliently alterable to allow its insertion through a pre-cut hole in a wall board.
2. Prior Art
Common commercially available devices for fastening an article to the wall board of a typical building interior wall, using a pre-cut hole, have a construction such as shown in FIG. 3 with a pair of pivoting anchor arms that are urged by a spring into the spread configuration shown. These arms may be urged to a streamlined configuration, with small frontal profile, to allow insertion through a mounting hole. When fully inserted therethrough the arms will spring open. The tightening of the bolt, which is mounted through an article to be attached to a wall, will pull the arms into engagement with the inner surface of the wall, which most commonly is so called dry wall, composed of a compressed gypsum or gypsum-like particulate material. While such conventional devices are simple and easy to use, they have drawbacks which limit their effectiveness. Leading edge portions 12, of a mounted prior art device, will compress against a wall board surface and embed somewhat therein by virtue of significant pressure exerted along the relatively narrow surface presented by these edge portions. When the particulate inner structure of a typical dry wall is pierced in this manner, an initially secure anchoring can be progressively loosened and weakened, because of vibration of the fastener. The tendency of these conventional devices, is to pierce the wall board, and they will also lead to deterioration of the structural integrity of the wall.
Some other wall fastener designs are proposed in U.S. Pat. Nos. 4,004,486 and 3,373,647. These devices appear inadequate for application to wall board applications since they rely on an anchor portion that must make binding engagement with the crumbleable inside of a predrilled hole.